Smoke eliminator heating element mounting for heat-cleaning cooking ovens



c. J. HOLTKAMP 3,470,353 SMOKE ELIMINATOR HEATING ELEMENT MOUNTING Sept.'30, 1969 I FOR HEAT-CLEANING cooxms OVENS Filed Oct. 9, 1967 FIG.|

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FIG. 3

FIG. 4

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mmh v MO CM Ek R WM m H M J T? w 1'' WWW United States Patent O SMOKE ELIMINATOR HEATING ELEMENT MOUNTING FOR HEAT-CLEANING COOK- ING OVENS Calvin J. Holtkamp, Mansfield, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 9, 1967, Ser. No. 673,887 Int. Cl. F27d 11/00; A21d N US. Cl. 219393 Claims ABSTRACT OF THE DISCLOSURE Mounting arrangement for a heater in a heat-cleaning oven of the type in which the heater is located closely below a plenum into which combustion products from the oven pass, the heater being supported by tabs lanced down out of the lower wall of the plenum in an array corresponding to part of the heater array, the openings from which the tabs are displaced serving as part of the inlet openings into the plenum, the heater being spaced from the lower wall of the plenum by embossments in the lower wall.

BACKGROUND OF THE INVENTION Field of the invention The invention pertains to the art of smoke eliminators for heat-cleaning cooking ovens.

Description of the prior art Kastovich US. patent application Ser. No. 552,663, filed Apr. 26, 1966, discloses and claims a smoke eliminator arrangement for a heat-cleaning cooking oven in which the smoke elimination is effected by the provision of an electrical heating element in a location closely underlying the top wall of the oven, with the top wall being provided with vent opening means arrayed to coincide with the array of the heating element. In this arrangement the heating element, in addition to performing its normal heating function in certain operations of the oven, also provides a smoke eliminating function as the smoke and cooking odors sweep thereover and out of the vent opening means. The mounting arrangementfor the heating element as disclosed in that patent application, and as embodied in current commercial apparatus produced by the assignee of that invention, comprises a series of cross stringers extending transverse to the main run lengths of the heating element and provided with notches to accommodate these heating element runs. A strap is secured along each stringer to capture the runs of the heating ele ment in these notches. A smoke eliminator heating element of that fashion performs satisfactorily but is exmnsive to manufacture, principally because of a high labor cost and the substantial number of pieces required to mount the heater.

SUMMARY OF THE INVENTION The principal object of this invention is the provision of a mounting arrangement for the smoke eliminator heater which is of substantially reduced cost, and which will provide satisfactory performance for most purposes.

This object is accomplished in accordance with the invention by forming the means for securing the heater element to the exhaust gas plenum from portions integral with the lower wall of the exhaust plenum, as well as providing any spacing means to be used between the heating element and the lower wall of the plenum by the wall itself. Specifically, in accordance with the preferred embodiment a series of tongues or tabs are lanced out to project downwardly from the lower wall of the plenum and are provided with end portions which support the 3,470,353 Patented Sept. 30, 1969 ice DRAWING DESCRIPTION FIGURE 1 is a partly broken side view of a range including a heat-cleaning oven incorporating the heater mounting arrangement of the invention;

FIG. 2 is a bottom view of the plenum with the heater mounted thereon;

FIG. 3 is a vertical sectional view corresponding to one taken along the line IIIIII of FIG. 2;

FIG. 4 is a bottom view of the lower wall of a fragmentary portion of the plenum with the tabs lanced out of the lower wall and an embossment provided, but before the heater is secured in place; and

FIG. 5 is a bottom view of the same fragmentary portion as FIG. 4, but with the heater secured in place.

PREFERRED EMBODIMENTS FIGURE 1 illustrates a representative type of cooking range 10 in which the smoke eliminator of the invention may be incorporated. Only those parts of the construction bearing reasonably directly upon an understanding of the invention will be noted herein, and referece should be had to the noted Kastovich patent application for a fuller explanation of the operation of the heat cleaning oven as a whole. For purposes of understanding this invention, the oven cavity 12 is defined on all sides except the front by an oven liner 14 about which heavy insulation 16 is provided. The opening in the front of the cavity is closed during cooking and during the heat-cleaning operation by the heavily insulated door 18.

The top wall 20 of the oven liner has secured thereto a shallow, pan-shaped member 22 which, with the liner top wall 20, generally defines the exhaust plenum 24. The lower wall 26 supports a heating element 28 closely therebelow. This heater 28 is the source of heat for broiling and operates at a reduced rate for baking. Also, in accordance with the teachings in the noted Kastovich patent application, the heater 28 is the source of heat for carrying out a heat-cleaning operation in the oven cavity, and further serves as the smoke eliminator and oxidizing element for the gaseous products produced during a heat-cleaning cycle of the oven. These gaseous products are subject to further oxidation by the high heat they encounter as they sweep closely by the heater 28 and into the plenum 24 before passing through the outlet vent 30 into the room.

In accordance with this invention the heater 28 is supported by a series of tongues or tabs integral with and depending from the bottom wall 26 of the plenum, the lower portions of the tabs being shaped to embrace the heater at spaced locations. The heater presents a generally serpentine array as shown in FIG. 2. As such it includes six front to rear passes 28A, five circular portions 28B connecting the front to rear passes and two converging rear portions 28C which terminate in a plug-in terminal at the rear wall of the liner.

The preferred arrangement is to provide tabs only along the straight runs 28A of the heater, and with the tabs along each such run 28A alternating from side-toside of the heater along the length of the run. Thus the tabs designated 32 are punched down to lie along one side of a run 28A of the heater while the tabs designated 34 are punched down to lie along the other side of the run 28A.

As may be best seen in FIGS. 4 and 5, for each tab displaced downwardly out of the plane of the lower wall 26 of the plenum, an opening 36 is left in the wall. After the heater 28 is installed these openings 36 lie closely ment of this invention provides quite satisfactory results,

above the runs 28A of the heater and serve as at least a part of the total inlet openings to the plenum. In fastening the heater in place, the unsecured end or lower portions of the alternating tabs 32 and 34 are bent over toward each other (FIGS. 3 and 5) and against the heater to form the cradles which secure the heater to the lower wall.

To the extent that it is desirable to space the heater 28 from the wall 26 a given distance, in accordance with the invention spacing means integral with the wall 26 are provided. The spacing means comprise the embossrnents 38 which are pressed down to lie below the plane of the remaining lower surface area of the lower wall 26. These embossrnents 38 may conveniently be located to alternate with the tab openings 36, and also at intermediate cations along the curved portions 28B of the heater and the converging portions 28C. The embossrnents illustrated are orientated to extend transverse to the lie of the contacting heater run, although they may have other orientations or other shapes.

It will be appreciated that the preferred lancing arrangement, in which the lanced tabs are provided only along the straight portions 28A of the heater, is intended to avoid restraining expansion and contraction of the heater relative to the supporting wall 26 during temperature changes encountered during heat-up and cool-down. It will also be appreciated that while the lanced tab arrangement provides substantially greater open area 36 at each tab location than the somewhat smaller and more numerous individual openings taught in the noted Kastovich patent application, that additional openings may be provided without the corresponding tabs at other locations along the array presented by the heater. For example, additional openings without tabs may be provided along the curved portions 283, and the rear portions 280. Or, if desired, the tabs from additional openings along the heater portions 28B and 28C may be located to provide support for such portions only when the heater is in a fully expanded position or a fully contracted position.

' It is also noted that the smoke eliminating performance of an arrangement according to the Kastovich patent application will usually be superior to that available with an arrangement according to this invention. This is due principally to the requirement that the holes 36 be relatively large to provide adequate tab material, as contrasted to the smaller and more numerous openings in the tabless construction of the Kastovich teachings. However, in many cases where the load to be cleaned is anticiwith substantial economy in manufacturing cost obtained.

I claim as my invention:

1. In a self-cleaning cooking oven having a plenum having a metallic lower wall and having a smoke eliminator of the character in which a rigid, sheathed, electrical resistance heater is disposed closely below said lower wall of the plenum into which combustion products from the oven pass, a mounting arrangement for said heater comprising:

a series of tabs integral with said lower wall and depending therefrom in an array coincident with at least a portion of the array presented by said heater, said tabs being shaped to include lower portions supporting said heater closely below said lower wall, said lower wall including openings defined therein by the areas from which said tabs are displaced, said openings serving as at least part of the inlet means for said combustion products passing into said plenum.

2. In an oven according to claim 1 including:

means spacing said heater downwardly from the plane of the lower surface of said lower wall.

3. In an oven according to claim 2:

said spacing means comprise downwardly directed embossrnents in said plenum lower wall.

4. In an oven according to claim 1:

successive ones of said tabs along a given length of said heating element alternate along opposite sides of said heater.

5. In an oven according to claim 1:

said heater presents .a generally serpentine array including a series of parallel substantially straight lengths, said tabs being provided along said straight lengths only.

References Cited UNITED STATES PATENTS 2,539,265 1/ 1951 Musgrave 338-315 X 2,729,735 1/ 1956 Fries 219398 2,922,018 1/ 1960 Walkoe 219-393 FOREIGN PATENTS 615,069 12/ 1948 Great Britain.

VOLODYMYR Y. MAYEWSKY, Primary Examiner U.S. Cl. X.R. 

